EarthAlmanac
New Chemical Digs Deep
Into Exxon Valdez Oil
More than five years ago the
Exxon Valdez plowed into
a reef in Alaska's Prince
William Sound and coated some
1,500 miles of shoreline with oil
(NATIONAL GEOGRAPHIC, Jan
uary 1990). Despite an
expensive cleanup, after
effects continue to harm
wildlife and commercial
fisheries, critics charge. A
civil suit filed against Exxon
by fishermen, property owners,
and natives that may total bil
lions of dollars is now in court.
On some beaches oil remains bur
ied deep among cobbles and boul
ders. But a new weapon called
PES-51 is exhuming that stubborn
subsurface goo. A biodegradable
hydrocarbon cleaner, PES-51
releases oil molecules from both
porous and nonporous surfaces,
causing the oil to float on water.
"We got about 150 gallons of oily
liquid out of the ground," says Steve
Rog, the environmental geologist
who oversaw the first test of the
chemical last year at Sleepy Bay on
Latouche, an island hit hard in 1989.
There the chemical was injected
into the rocky beach (above), which
was then flushed with seawater.
The oil was collected by skimmers
and booms.
PES-51 may also
keep future oil spills
from adhering to
beaches, Rog says.
Sprayed on before a
slick hits, it would cre
ate a nonstick film,
allowing the oil to slide
back into the sea.
Grizzlies Feast
on a Mountain
of Moths
lowly insect-the
army cutworm
-
moth-is one
of the most important
foods for a third of the
some 300 grizzly bears
in the Yellowstone
National Park area.
Each summer millions
of moths migrate from
the Great Plains to
TALIEB. FOBES peaks above 10,000 feet
to feed on wildflower nectar and
shelter in the rocky slopes.
At lower elevations during this
time bears feed on roots, clover,
grasses, and a few insects. But oth
ers have learned to climb to a ban
quet in the sky, digging the moth
morsels out of the rocks.
"One bear may eat 20,000 moths
a day," says Steve French. Among
several researchers studying this
popular topic, Steve and his wife,
Marilynn, have investigated the
behavior for seven years. "The
Smoths can be 80 percent fat and
20 percent protein," Steve
reports. "Some bears feed on
them for eight hours a day."
Until recently such alpine
areas had not been con
sidered important grizzly
habitat. French worries
because many lie outside
-
the park in national for
S
ests and are vulnerable
to oil and gas drilling,
mining, and develop
ment as ski resorts.
"Now we may have to
protect those alpine
-
sites," he says.
NationalGeographic, August 1994